U.S. Pat. No. 3,545,686 issued Dec. 8, 1970 on the application of G. N. Brown, discloses a film shredding device wherein film to be shredded is fed through a pair of cooperating saw-toothed blades, one of which is stationary and the other of which rotates therepast in interdigitated relation. At each passing of the blades, film is said to be pierced and torn. The device, with its blades of interdigitated teeth, requires careful attention to blade clearances and frequent adjustment of those clearances.
U.S. Pat. No. 4,004,738 issued Jan. 25, 1977 on the application of W. E. Hawkins, discloses a film shredding device wherein a film web of narrow width is pierced and torn by being pulled across a stationary, free-standing, saw-toothed blade and the torn film is then cut or further torn by being fed through pairs of closely-spaced, smooth-edged blades. While the device of that patent is said to reduce the tendency for jerking the input film material, use of the device is inherently limited to narrow film widths because the shredding element of that device is required to have a diameter at least two times the width of the film to be shredded.
In previous shredding devices, it has been found that pairs of blades with intermeshing teeth are difficult to adjust and maintain in adjustment and pairs of blades with smooth cutting edges do not always sever all of the film which passes through. When film enters a shredding device and is incompletely cut, then the incompletely cut film is subject to being wrapped about the rotating parts of the device and to being, thereby, jerked further into the device at the speed of the rotor unless or until the film is completely severed.